Eclipse Marketplace error - Unexpected exception: org/eclipse/equinox/internal/p2/repository/RepositoryTransport

This problem raises because you could not access your Internet via eclipse. There could be a solution among answers listed above. I solve this problem with different approach. Linux has built-in SSH support to it is always important to check the local host address. And also no need to bypass traffic. So you can Go to

Window-> Preferences -> General -> Network Connection.

Now remove the proxy bypass and clear SOCKS IP.

NOTE:- This will work if your have proxy server. Thank You

I experienced this issue when the SOCKS proxy in eclipse was incorrectly configured. My machine which sits in a LAN connects to the internet using an HTTP proxy. In the Network Connections tab in eclipse, i had configured the HTTP, HTTPS and SOCKS proxy. The SOCKS proxy was not required in this case, and on clearing the SOCKS proxy, the error disappeared and Eclipse Marketplace became accessible...woohoo !!

Resolution Steps

1. In Eclipse, click Windows -> Preferences
2. Search for 'Network Connections' in the 'filter' textbox
3. Set HTTP and HTTPS proxies correctly ( If you are connecting to the internet using a proxy)
   Note : If you are connecting to the internet without proxy, use the 'Direct' profile setting in the 'ActionProvider' drop down. Else use the 'Manual' setting.
4. Set SOCKS proxy ( If you have a SOCKS proxy server configured), otherwise clear this row.
5. Apply the changes and save it.

Now Marketplace should become accessible for you.

For details on Network Connections configuration in Eclipse, use the following link

http://help.eclipse.org/juno/index.jsp?topic=%2Forg.eclipse.platform.doc.user%2Freference%2Fref-net-preferences.htm&_sm_au_=iDMfvB6nQs52SSSM

I have installed version 3.7.2 of eclipse indigo and run into the exact same issue (after a clean eclipse/marketplace install). I resolved the problem by updating the marketplace plugin to a more recent version (in eclipse go to "Help -> Check for Updates" and the update should be listed there).